B737-200 JT8D -15 and 17 Reduced thrust N1
Normal take off EPR is 2.10 bleeds on for 20C. The operator uses 1.99 EPR as a reduced thrust figure for an assumed temp of 40C. Actual OAT 20C. The QRH N1 for EPR 1.99 for 20C is 94 percent and for 40C is 97 percent. When calculating the EPR versus N1 crosscheck on the take off data card, which N1 figure is the valid one?
My understanding is that the N1 for the actual OAT is the correct one to use. However the operators uses the N1 for the assumed temp of 40C. This seems a bit dodgy to me.